ABSTRACT
<p><b>OBJECTIVE</b>To investigate the chemical compounds from the ethanol extract with inhibitory effects against aldose reductase from Thunbergia.</p><p><b>METHOD</b>Guided by anti-aldose reductase assay, compounds from the bioactive fraction (ethyl acetate extract) were separated and purified by various chromatographic methods including silica gel, Sephadex LH-20, and reversed-phase HPLC. Their structures were indentified based on analysis of the spectroscopic data including 1D and 2D NMR data.</p><p><b>RESULT</b>Eight compounds were obtained and identified as 8-hydroxy-8-methyl-9-methene-cyclopentane [7,11] -1,4, 6-trihydroxy-tetrahydronaphthalene-12-one, named as thunbergia A (1), 3,4-dihydro-4,5,8-trihydroxy-2-(3-methyl-2-butenyl) naphtha[2,3-b] oxiren-1(2H)-one (2), 8-(beta-gluco pyranosyloxy)-3,4-dihydro-2-(3-methyl-2-butenyl)naphtha [2,3-b] oxiren-1(2H)-one (3), galangin (4), quercetin (5), luteolin (6), 5,6,3',4'-tetrahydroxy -3,7-dimethoxy-flavone (7) and upeol (8).</p><p><b>CONCLUSION</b>Thunbergia A was a new derivative of tetrahydronaphthalene, and compounds 2 and 3 were separated from the genus Thunbergia for the first time.</p>